Foreign travelers or even local people carry cash and thus are exposed to loss or theft of the cash. Carrying big amount of cash would cause an inconvenience and a crime while carrying small amount of cash would cause another inconvenience of frequent withdrawal or exchange whenever necessary. An alternative measures to cope with this kind of problem is an electronic money or e-money. The e-money, however, has a pitfall that it lacks such functions as user authentication and therefore it is virtually impossible to be returned if lost.